Since I am going to be swapping a 4.3 into my trans am I was just curious how much detail they go into. I am planning on a 4.3 vortech with passenger car TBI and so on to give the impression it came from a passenger car. A Y-pipe and exhaust manifolds are a area of concern so what do you tell them? when obviously theres no Y-pipe that was ever designed for a f-body. I'm going to do the swap after my next smog test so that will give me 2 years to fool around and get everything right. And yes a typhoon engine did cross my mind but need it for economy LOL .... NowI have seen pretests where it never really states what type of fuel injection system is associated with the VIN number so could I adapt port injection to a 4.3 and pass a referee test? ..... for instance I have a 82 vette, when it's smogged the printout just says fuel injected so what I'm asking is why would they care if it had TBI or port EFI. Tell me about what they failed you for on your conversions!

 

85-87 G-bodies (El Camino, Monte Carlo) had 4.3L V6's, so you need that whole setup. They require 100% of the engine from the donor car, and they very rarely let something slide. You're also not allowed to put a truck engine into a car so dont tell them its a truck engine.
You couldnt "adapt" an intake manifold unless that type of intake was offered on a passenger car. Basically they're looking for something all stock. If its not stock then it better be 50-state approved parts for a car, not a truck.
You can install TBI or TPI V8, that is ok.

 

I know up to like 93 maybe 92 the caprice or some boat like that got the 4.3 v-6 tbi motor so that would at least get me a balance shaft variant. I also know the early monte carlos had factory shorty headers so that laeves a little open. Maybe I could have my edelbrock bar label affixed to a set of custom headers and fool them as well. The cars a 82 so I could say the motor is from any year almost but yea I know it has to be from a passenger car. But do they honestly check engine casting numbers or is it more of a visual inspection.

 

The best thing to do is call them before you do it to see what is required. I just went through this with a 82 Corvette LS1 swap. It required all the Emission controls and Warning lights from the donor car. You have to have a speedometer that works and is acurate. And if they want you to change something after the first inspection make sure you go back to the same inspector. Good luck!!

 

Before you get too wrapped up in this swap, you need to understand 6 cylinder propaganda is just that ...false economy. I have the 350 V8 that is modded for high output and still gets 25 MPG on the road. What you need is fuel injection, not a carb.

 

I have fuel injection.

 

I guess I forgot...you have TBI right?
If so, then you must need tuning.
The problem there is, it's quite techical...not for the faint at heart.
The V-6 tuning is going to be the same.
You will have to have the right ECM and PROM for the application you are using.
I'm just trying to alert you to all the situations you might run into doing that swap.
I have done one on a '83 El Camino....never again!
By the way...he was never happy....wished he had gone V-8 tuned port.

 

I'm with Don. You want to yank a 350 V8 to drop in a 4.3 V6??? All for fuel economy??? My personal feeling is that you will be disappointed.

Why not just shop around and spend the money on a good used economy car for daily driving?

 

Yea but keep in mind I have a corvette to which is why the trans am is destined for economy ....Yes DynoDon it is basically a L-98 with LO-3 TBI, 3.73 gears and a 5 speed. I used it on all freeway driving last week and ugggghhh about 19mpg .... But yea it's in a different zip code on it's tuning it way off I would think.7747ecm .. suburban chip ... 305 injectors and god knows how old they are and 305 knock sensor and est module .... I guess for whats in it it's doing semi-good LOL ..... A true hybrid

 

Wow you have a lot of options to get better fuel mileage on that combination without pulling the engine out and replacing it. Here's my opinion on what you might want to address before making such a drastic a change.
#1 Finish the 350 swap....IE install 350 injectors,chip, knock sensor and est
module
#2 Replace the 3.73's with 3.08's.
#3 Do a full tuneup if needed. Plugs, plug wires, dist cap/rotor, oxygen sensor, coil etc.
#4 Chip tuning.

Even doing all that will be alot cheaper and take alot less time than a V6 swap.

 

The other thing to keep in mind for any v-6 swap is that it must be an engine from the same year or newer including all smog equipment and computer from the doner car. Since your T/A is a 1982 according to your sig, you would need to find a car based v6 not a truck based unit. It would have to come from something newer than 1982 and must be pretty much bone stock. Once you got it passed the referee, you could probably get away with some mods that don't look to crazy as long as it will still pass the sniffer. Most smog techs won't know what is/was available on the engine in a car that old, and won't bother to look it up unless you give them reason to think it is not smog legal. In the case of the referee, if he doesn't know, he will have a book telling him exactly what to look for and he will not only look for everything in the book, but he will be specifically looking for a "hot rodder" to be trying to slip something by him. I think that for the ultimate economy f-body, your car with a roller cam 305 with speed density tpi, a peanut cam, and an economy tune up will get as good mileage as any 4.3 v6 you could find.

Don had an Rs 305 tbi that he converted to tpi, but left in the peanut cam, and did a custom tune on the chip and averaged better than 30 mpg on trips to Reno and on another trip to Vegas, including the around town driving he did in Reno and Vegas.